The present invention relates to airduct mufflers, and more particularly to mufflers in systems particularly useful to provide assisted breathing for those persons who need a forced-breathing therapy, and more particularly as primarily now considered the dispensing of air to a person having respiratory problems such that air under pressure is forced upon the patient in alleviating his distress and breathing difficulties.
Even more particularly, as presently considered, equipment of the type of this invention is especially considered for use in the treatment and distress-relieving of a disease known as apnea, which is a respiratory disorder in which patients fail to breathe sufficiently or properly during sleep, recognized types being obstructive sleep apnea and central sleep apnea.
These are dreadful conditions, sometimes even life-threatening, and at least can cause devastating effects of changes of personality, family life problems, diminished work performance, irritability, impotence, insomnia, memory loss, etc., as the patient undergoes the loss of breathing repeatedly during sleep, even a minimum of such episodes to be considered as a medically significant being more than five episodes of cessation of airflow for at least ten seconds each, per hour of sleep.
Any other respiratory problem complicates the condition.
Tracheotomy, tonsillectomy, and uvulopalatopharyngoplasty, and combinations thereof, have been used to try to surgically correct the condition or alleviate the symptoms; and various drug therapies, and physical equipment such as rocking beds, iron lungs, body shells, and various ventilators have been tried.
Forms of ventilators known as CPAP (continuous positive airway pressure) have helped reduce the number of tracheotomies, these being devices with a blower/motor assembly, a flexible hose, and a tight-fitting nasal mask, by which air (sometimes with extra oxygen, and/or humidity control) is forced onto a patient, the pressure being always above atmospheric (i.e., "continuously positive"), thus above atmospheric during inhalation as well as exhalation.
And even though the use of CPAP ventilators is a significant bother and nuisance to a patient, it is better than many alternatives, so a patient has no realistic alternative to their use.
The above is given as an introduction to the long-recognized problems in this field, and the attempts to cure or relieve these problems, generally from the article "Broken Sleep", by Terrie Weaver and Richard P. Millman, as published in American Journal of Nursing (Feb., 1986) p. 146-150, having an extensive bibliography.